Hot damn, quite right. That's what I get for going off memory.Nonamer wrote:(Also, you're about 2 orders of magnitude wrong about the density of air, which is about 1.2 kg / m^3).
Thanks!
Interesting. So is it safe to say that, assuming the ship isn't an unexpectedly heavy object, then nothing is amiss and the impact is totally consistent with a falling object of that size?Jedi Master Spock wrote:As a matter of fact, the amount of kinetic energy that is transmitted into seismic effects in an impact tends not very large.
While they're talking about very high velocity impactors, the WTC towers are indeed somewhere around the ballpark we're talking about in terms of energy and velocity, and are largely assumed to have been in near-freefall in terms of how fast they hit the ground. So:
Each tower had around 1e12 joules of gravitational potential (sure, the assumptions are simplified there, but it's good to within +/- 0.5 orders of magnitude with those sorts of assumptions), and the impact of the north tower falling was a 2.3 Richter event - i.e., ~180 megajoules, or on the order of 1.6e-4.
As it turns out, most calculations of the GPE of the WTC are a bit lower, meaning it's quite appropriate to round back down to the figure the impact calculator uses, of 1e-4.
Using that figure, we would have a Richter 3.2 seismic event from a 10 kiloton impact of a coreship - i.e., a shudder of the earth that could easily be overlooked, and one that we can easily imagine failing to knock over droids in formation.